Beverage dispensing systems are typically used in beverage dispensing establishments for efficiently dispensing large quantities of beverage. Typically, beverage dispensing systems are used to dispense carbonated alcoholic beverages such as draught beer and cider. However, also non-alcoholic carbonated beverages such as soft drinks may be dispensed using a beverage dispensing system. Beverage dispensing systems are mostly for professional users such as in establishments like bars, restaurants and hotels, however, increasingly also for private users such as in private homes.
Professional beverage dispensing systems typically dispense beverage provided in large beverage containers. Such beverage containers may hold 20-50 liters of beverage for a professional beverage dispensing system for allowing typically 50-100 beverage dispensing operations before needing to exchange the beverage container. Conventional beverage containers are made of solid materials such as steel and re-filled a number of times. Recently, beverage containers have been made collapsible and for single use only due to hygiene concerns when refilling solid beverage containers. An example of a beverage dispensing system using collapsible beverage containers is the DraughtMaster™ system provided by the applicant company. Such beverage dispensing systems using collapsible beverage containers typically have the beverage container installed in a pressure chamber. Some examples of prior art beverage dispensing systems follow below:
In WO 2007/019848, a beverage dispensing system is described. The beverage dispensing system comprises a pressure chamber, which is adapted to accommodate a beverage container of collapsible material.
In WO 2009/024147, a module for a modular beverage distribution system is disclosed. Each system comprises a frame, a pressure chamber and connectors for receiving pressure fluid and for supplying the pressure fluid to the pressure chamber and to the neighbouring module. The system has a separate rinsing line. By using a specially designed discharge valve, alternatively rinsing fluid or beverage may enter the tapping line. Rinsing fluid is provided from a separate pressurized reservoir. The discharge valve includes safety features for avoiding mixing rinsing fluid and beverage.
In WO 2010/029122, a method of cleaning the tapping line of a beverage dispensing system is disclosed in which a cleaning and flushing cartridge for internal use is described. The cleaning and flushing cartridge is installed in the pressure chamber similar to a beverage container and dispensed similar to a beverage.
WO 2010/060946 and WO 2011/117192 both relate to a method of cleaning the tapping line of a beverage dispensing system in which a cleaning and flushing cartridge for external use is described. The cleaning and flushing cartridge is installed outside the pressure chamber and has a pressure fluid source connected. The rinsing and flushing fluid is dispensed similar to a beverage.
WO 2010/060949 relates to a beverage dispensing system having a first and a second detector for generating a control pressure. The method comprises evaluating the control pressures from the control pressure outputs of detectors for determining the operational mode of the beverage dispensing system.
In WO 2010/020644, a method of installing a collapsible beverage container in a beverage distribution unit is disclosed. The method comprises the steps of positioning the collapsible beverage container in a sloped position, pivoting the collapsible beverage container in a rotational motion around a support surface and sliding the collapsible beverage container on the support surface.
When using long dispensing lines, a significant amount of beverage will remain in the tapping line when the beverage container is empty. In order to avoid that this beverage flows backwards through the tapping line, it is contemplated that a non-return valve may be used in the tapping line. Further, in order to prevent dripping, a spring loaded valve may be used. An example of a beverage dispenser including a plurality of valves is DE 296 04 703 U1, in which an electrical liquor dispensing system is disclosed. The tapping line has a non-return valve and a spring loaded lid. The liquor is propelled from a container through the tapping line by an electrical pump and explicitly not by pressurized gas.
When dispensing beverage from the beverage dispensing system using a collapsible beverage container, a pressure fluid, typically a gas, is allowed to enter the pressure chamber. During the dispensing of beverage from the pressure chamber, the pressure fluid acts on the collapsible beverage container and forces the beverage out of the pressure chamber while simultaneously crumpling the collapsible beverage container. The volume of the crumpled collapsible beverage container is thereby reduced corresponding to the amount of the dispensed beverage. The collapsible beverage container is made of flexible and preferably disposable materials such as thermoplastic materials.
The interior of the collapsible beverage container is divided into a beverage space constituting carbonated beverage and initially occupying the majority of the interior of the beverage container and a head space filled with gas, primarily constituting CO2 gas.
While performing a dispensing operation, the force applied to the beverage container by the pressure in the pressure chamber causes the beverage to flow out of the beverage container and into a tapping line. The tapping line leads to a dispensing device which may be located at a distant location such as one floor above the pressure chamber. The dispensing device typically has a tapping valve and a tapping handle for allowing an operator to control the tapping valve and thereby the beverage dispensing operation. The operator, such as a bartender or barmaid, uses the tapping device to control the rate of beverage dispensing.
A problem often observed when the beverage space of the beverage container is empty or almost empty is that the gas of the head space starts entering the tapping line. Such gas will result in gas bubble formation in the tapping line. The presence of gas bubbles in the tapping line will cause excessive frothing and aeration of the carbonated beverage at the tapping valve of the dispensing device. The carbonated beverage dispensed will thus be very foamy and will have a less than optimal taste and appearance. Typically, this beverage therefore has to be disposed of. This is also an indication for the bar employee to exchange the empty and crumpled collapsible beverage container with a new collapsible beverage container filled with beverage.
However, gas will still remain in the tapping line even after the beverage container has been exchanged. This will result in excessive foaming also for the first one or two servings of carbonated beverage. This beverage must be disposed of as well. Thus, the total loss of beverage may amount to 2-4 servings for each beverage container, i.e 1-2 at the beginning of each container and 1-2 at the end of each container, resulting in a loss of about 10% of the beverage included in a typical 20 liter collapsible beverage container.
In case a modular beverage dispensing system is used, i.e. a system wherein a single tapping line is fed from a multitude of collapsible beverage containers, the problem is even larger since the beverage spaces of the different collapsible beverage containers may be empty at different times, resulting in even more beverage lost.
The object of the present invention is thus to dispense beverage while preventing that any gas from the head space is entering the tapping line.